The 33-year-old musician will make her acting debut on the Showtime music drama, Roadies, this Sunday, and it all happened after meeting creator Cameron Crowe on the Internet.

“When I met Cameron Crowe years ago on Twitter, I felt like I’d met a kindred spirit. We both grew up with music and dreaming in our bones,” Williams exclusively tells ET. To see her in action, watch the exclusive NSFW sneak peek from the new episode above.

Years later, after Williams moved to the seaside town of Venice Beach, California, the two finally met in person, leading Crowe to entertain the idea of her stepping in front of the camera.

“One day, out of the blue, he told me that he had a hunch that I could act,” she recalls. “I laughed, but admitted that I’d always wanted to try my hand at it. He encouraged me, and said he’d love to have me come audition for a part he was working on.”

“Nearly a year later, after I’d all but given up on the idea, he called and asked me if I could come in to audition the next day,” explained Williams, who at that point had relocated to Nashville. “He encouraged me to fly out anyway and just try, so I did. I’ll never forget him calling to tell me I got the part. That was a good moment.”

For Williams, who formerly fronted musical duo The Civil Wars with John Paul White, acting was an entirely new challenge -- and one she was ready to take on.

“I definitely had nerves about treading into new territory, but going new places for me feels like the only way to grow. It’s good to get out of my comfort zone, and I learned a lot,” she says, adding that the cast and crew “were encouraging and patient" with the acting newbie.

The entire Roadies experience proved special for Williams, who pointed to her second day on set as being her most memorable.

“In the middle of shooting a scene with Rafe Spall, I looked up and saw [executive producer] J.J. Abrams standing in my direct line of sight. Talk about a distraction,” she shares. “We’d met prior, but hadn’t worked together until now. Without even turning his head, Rafe saw the look on my face and whispered, ‘J.J. is standing behind me, isn’t he.’ He knew. He just knew. I kept my cool, but barely!”

As a seasoned musician who’s toured the world, Williams said a lot of the elements in Roadies ring true, most notably “the deep love of music, the joy of collaborating each night on tour to make something bigger than yourself, the way being on the road keeps you living an adventure in close proximity with people who are not your family but become your family.”

“Also, I laughed so hard when I saw the ‘hot bag’ scene in episode four,” she reveals. “That is also real life on a tour bus, but maybe that’s too much personal information for this interview!”

As for what’s coming up next musically for Williams, she will release an acoustic version of her latest album, Venus, which includes two previously unreleased songs, on Friday. But, expect more to come in the very near future.

“I’m taking the music back to the front porch again, and it feels really good.”